Grey trisazo dyestuffs



United States Patent fabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Application April 7, 1954, Serial No. 421,673

Claims priority, application Germany April 18, 1953 4 Claims. (Cl. 260-169) stuffs and to a process of making the same; more particularly it relates to azo dyestuffs corresponding to the following general formula:

wherein A stands for the radical of l-amino-S-hydroxynaphthalene-sulfonic acid, B and C for middle components of the benzene or naphthalene series which may contain sulfonic acid groups, and D stands for a sulfonic The present invention relates to new grey trisazo dye- Holsacid of 2-amino-8-hydroxynaphthalene or l-amino-7- hydroxynaphthalene or derivatives thereof.

The new trisazo dyestufis are obtainable by coupling diazotized 1-amino-8-hydroxynaphthalene-sulfonic acids with an amine of the benzene or naphthalene series which may contain sulfonic acid groups and is capable of coupling in p-position to the amino group, diazotizing the aminoazo compound thus obtained and coupling it again with an amine of the benzene or naphthalene series which may contain sulfonic acid groups and is capable of coupling in p-position to the amino group, further diazotizing this amino disazo compound and coupling it in alkaline medium with a sulfonic acid of 2-amino-8-hydroxynaphthalene or l-amino-7-hydroxynaphthalene or the derivatives thereof. As first diazo components may be mentioned by way of example l-amino-S-hydroxynaphthalene-3-sulfonic acid, 1-amino-8-hydroxynaphthalene-3,6- disulfonic acid, as middle components l-amino-2-methoxy-S-methylbenzene, l-aminonaphthalene, l-aminonaphthalene-6- or -7-sulfonic acid, and as final components 1- amino-7-hydroxynaphthalene-3-sulfonic acid, 2-amino-8- hydroxynaphthalene-3,6-disulfonic acid.

The new trisazo dyestuffs dye cotton and regenerated cellulose reddish to greenish grey shades of good dischargeability. Compared with known comparable dyestufi's which do not contain sulfonic acids of 1-amino-8- hydroxynaphthalene as initial component, the new dyel a is further diazotized corresponding as free acid to the IFNOM stuffs are especially distinguished by a superior fastness to light.

present process are preferably first converted into their O-esters by reacting them with benzene or toluene sulfochloride and then diazotized. After the final coupling these esters are split by alkaline saponification.

The following examples illustrate the invention without, however, limiting it thereto; the parts being by weight:

Example 1 319 parts of l-amino-8-hydroxynaphthalene-3,6-disulfonic acid are diazotized as O-ester of benzene sulfonic acid in known manner and coupled with 137 parts of lamino-Z-methoxy-S-methy1benzene. The monoazo dyestuti is diazotized and combined with 143 parts of laminonaphthalene. The disazo dyestuif thus obtained and added to 319 parts of 2-amino- 8-hydroxynaphthalene-3,6-disulfonic acid in sodium carbonate alkaline solution. When the coupling is completed the dyestuif is saponified byheating with caustic soda solution. After neutralizing the trisazo dyestu fi formula (llO s is isolated anddried. It is a brown-black powder easily soluble in water which dyes cotton and regenerated cellulose reddish grey shades'fast to light;

Example 2' 00118 no no N=N N=N-N=N N112 '7 on, noassoln our SOaH is then isolated under neutral condition and dried. The

brown-black powder easily dissolves in water and dyes The sulfonic acids of 1-amino-8-hydroxynaphthalene used in the 1-aminonaphthalene-7-sulfonic then combined with 137 parts cotton and regenerated- 'oelhilose blue-grey shades fast tollightandrwellz dischargeable.

Example 3 319 parts of 1-amino-8-hydroxynaphthalene-3,G-disulfonic acid are diazotized as O-ester of benzene sulfonic acid, combined with 223 parts of l-aminonaphthalene-7- sulfonic acid, further diazotized and coupled with 137 parts of 1-amino-2-methoxy-S-methylbenzene. The fur- 1Q ther diazotized disazo dyestuff is combined with 239 parts of l amino 7-hydroxynaphthalene-3-sulfonic acid in aqueous pyridine. Thereafter it is saponified by means of caustic soda solution, isolated and dried. The trisazo dyestuff corresponds as free acid to the formula and is a grey-black powder easily soluble in water. It dyes cotton and regcneratedcellulose greenish grey shades very fast to light and very well dischargeable.

Wedaim: 1'. Trisazmdyestuffscorrespondingas-free-acids to the generali formula wherein B and C stand for radicals selected-from the groupconsisting of: radicals of the-benzene, and the naph thalene series bearing the N=N-- bridges in p-positionto; each other, with one of the radicals B and'C being substituted by=at least one and not more than two substituents of the group consisting of lower alkyl and lower alkoxy, and D stands for an amino-hydroxynaphthalenesulfonic-acid': selected from the group consisting of' lamino-7 --hydroxy-- and 2-amino-8 hydroxynaphthalenesulfonic acids bearingthe -N=N- bridge-in o-position the hydroxy group, m beingone of the integers 1 and 2.

q 2'. Trisazo dyestufis corresponding as free acids to the general formulawherein B and C stand for radicals selected from the group consisting of radicals of the benzene and the naphthalene series bearing the --N=N-- bridges in p-position to each other, with one of the radicals B and C being substituted by at least one and not more than two substituents of the group consisting of lower alkyl and lower alkoxy, m being one of theintegers 1 and 2.,

3. Trisazo dyestuffs corresponding as free acids to the general formula wherein B and C stand for radicals selected from the group consistingof:radicalsofithe benzene and the naphthalene series bearing the -N=N bridges in p-position to eachother, with one of theradicals'B'andC'being substituted by at least oneand'not" morethan: two. substitu:

ents of thegroup consistingof lower alkyl and'alower Reunion PATENTS 5,484 Great Britain of 1908 

1. TRISAZO DYESTUFF CORRESPONDING AS FREE ACIDS TO THE GENERAL FORMULA 